Re: how does each part of the taper affect line behavior?
I'm sounding like a broken record because I keep mentioning the term "delivery system." The rod and line is that. A rod with a short head heavy line will throw bulky popper fairly easily in short to medium distances. A rod with a longer and slender head won't throw out that same fly well at all, but it will throw a sparse bonefish fly 80 feet easily.
You could look at a Rio Tropical Clouser Taper. It has some extra mass in the head for turning over larger flies. It also has a longer and slender rear body for aerodynamics.
Just another thought. Get help with your casting. Subtle corrections could make a difference in your distance casting.